Method, electronic device and computer program product for storage management

ABSTRACT

Embodiments of the present disclosure relate to a method for storage management, an electronic device, and a computer program product. According to an example implementation of the present disclosure, a method for storage management is provided, which comprises receiving an access request for target metadata from a user at a node among a plurality of nodes included in a data protection system, wherein the access request includes an identification of the target metadata; based on the identification, acquiring target access information corresponding to the identification from a set of access information for the user, wherein the target access information records information related to access to the target metadata; and if the target access information is acquired, determining the target metadata based on the target access information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application202010790766.X filed on Aug. 7, 2020. Chinese Patent Application202010790766.X is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to storagemanagement, and in particular, to a method for storage management, anelectronic device, and a computer program product.

BACKGROUND

In a data protection system using decentralized metadata searchmanagement, as the number of users increases, so does the amount ofmetadata of the users. In this case, the search speed will besignificantly reduced. In addition, the users may log into the dataprotection system in different geographic locations to manage theirbackups stored in the data protection system through search. However, itis difficult to ensure consistent user experience in the backupsearching process in different geographic locations.

SUMMARY OF THE INVENTION

Embodiments of the present disclosure provide a method for storagemanagement, an electronic device, and a computer program product.

In a first aspect of the present disclosure, there is provided a methodfor storage management. The method includes: receiving an access requestfor target metadata from a user at a node among a plurality of nodesincluded in a data protection system, wherein the access requestincludes an identification of the target metadata; based on theidentification, acquiring target access information corresponding to theidentification from a set of access information for the user, whereinthe target access information records information related to access thetarget metadata; and if the target access information is acquired,determining the target metadata based on the target access information.

In a second aspect of the present disclosure, there is provided anelectronic device. The device includes at least one processing unit andat least one memory. The at least one memory is coupled to the at leastone processing unit and stores instructions configured to be executed bythe at least one processing unit. The instructions, when executed by theat least one processing unit, cause the device to perform actions. Theactions include: receiving an access request for target metadata from auser at a node among a plurality of nodes included in a data protectionsystem, wherein the access request includes an identification of thetarget metadata; based on the identification, acquiring target accessinformation corresponding to the identification from a set of accessinformation for the user, wherein the target access information recordsinformation related to access the target metadata; and if the targetaccess information is acquired, determining the target metadata based onthe target access information.

In a third aspect of the present disclosure, there is provided acomputer program product. The computer program product is tangiblystored on a non-transitory computer-readable medium and includesmachine-executable instructions; and the machine-executableinstructions, when executed, cause a machine to perform any step of themethod described according to the first aspect of the presentdisclosure.

The summary is provided to introduce the selection of concepts in asimplified form, which will be further described in the detaileddescription below. The summary is neither intended to identify keyfeatures or essential features of the present disclosure, nor intendedto limit the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

By description of example embodiments of the present disclosure in moredetail with reference to the accompanying drawings, the above and otherobjectives, features, and advantages of the present disclosure willbecome more apparent. In the example embodiments of the presentdisclosure, the same reference numerals generally represent the samecomponents.

FIG. 1 shows a schematic diagram of an example of a storage managementenvironment in which some embodiments of the present disclosure can beimplemented;

FIG. 2 shows a flowchart of a method for storage management according tosome embodiments of the present disclosure;

FIG. 3 shows a schematic diagram of an example of access informationaccording to some embodiments of the present disclosure;

FIG. 4 shows a schematic diagram of an example of a storage managementprocess in the case where target access information has expiredaccording to some embodiments of the present disclosure;

FIG. 5 shows a schematic diagram of an example of a storage managementprocess in the case where target access information has not expiredaccording to some embodiments of the present disclosure;

FIG. 6 shows a schematic diagram of an example of a storage managementprocess in the case where target access information is not acquiredaccording to some embodiments of the present disclosure; and

FIG. 7 shows a schematic block diagram of an example device that can beconfigured to implement an embodiment of the present disclosure.

In the accompanying drawings, identical or corresponding referencenumerals represent identical or corresponding parts.

DETAILED DESCRIPTION

Preferred embodiments of the present disclosure will be described inmore detail below with reference to the accompanying drawings. Althoughthe preferred embodiments of the present disclosure are shown in theaccompanying drawings, it should be understood that the presentdisclosure can be implemented in various forms and should not be limitedby the embodiments set forth herein. Rather, these embodiments areprovided to make the present disclosure more thorough and complete andto fully convey the scope of the present disclosure to those skilled inthe art.

The term “include” and its variants as used herein indicate open-endedinclusion, i.e., “including, but not limited to.” Unless specificallystated, the term “or” indicates “and/or.” The term “based on” indicates“based at least in part on.” The terms “an example embodiment” and “anembodiment” indicate “at least one example embodiment.” The term“another embodiment” indicates “at least one additional embodiment.” Theterms “first,” “second,” and the like may refer to different oridentical objects. Other explicit and implicit definitions may also beincluded below.

As mentioned above, traditionally, in a data protection system usingdecentralized metadata search management, an increase in the number ofusers will lead to an increase in metadata, which leads to a decrease insearch speed, so the expansion of the traditional data protection systemis limited.

In addition, the users are mobile, and they may log in to the dataprotection system at different times and in different geographiclocations to manage their backups stored in the data protection systemthrough search. For example, a user may log into the data protectionsystem in the UK on Monday, and log in to the data protection system inChina on Wednesday. In this case, it is difficult to ensure consistentuser experience during the backup searching process at different timesand different geographic locations.

Further, different users may have different search preferences. Forexample, the data protection system may open more search functions toadvanced users, but only limited search functions to ordinary users.However, the traditional data protection system does not supportsearching based on users' search preferences.

According to an example embodiment of the present disclosure, animproved solution for storage management is proposed. In this solution,an access request for target metadata from a user is received at a nodeamong a plurality of nodes included in a data protection system, wherethe access request includes an identification of the target metadata;based on the identification, target access information corresponding tothe identification is acquired from a set of access information for theuser, wherein the target access information records information relatedto access the target metadata; and if the target access information isacquired, the target metadata is determined based on the target accessinformation.

In this way, the solution stores the access information in the localnode where the user logs in, so that the local node may quickly providethe user with metadata content in the access information as the targetmetadata. In addition, because the access information is user specific,it can support searching according to the user's search preferences.Therefore, the storage efficiency and user experience may, in one ormore embodiments of the invention, be significantly improved.

In the following, specific examples of this solution will be describedin more detail with reference to FIG. 1 to FIG. 7 . FIG. 1 shows aschematic diagram of an example of storage management environment 100according to some embodiments of the present disclosure. Storagemanagement environment 100 includes data protection system 110 and user120.

Data protection system 110 includes a plurality of nodes, such as nodes130-1 to 130-3 (hereinafter, collectively referred to as “node 130”).Node 130 stores access information, such as access information 140-1 to140-3 (hereinafter, collectively referred to as “access information140”). Access information 140 records information related to an accessto metadata. It should be understood that the number of nodes 130 andthe amount of access information 140 are only exemplary, data protectionsystem 110 may include any suitable number of nodes 130, and nodes 130may store any suitable amount of access information 140.

In some embodiments, the access information is specific to user 120. Inthis case, node 130 may group the access information of multipledifferent users into corresponding multiple groups of accessinformation. For example, node 130 may use multiple access informationlists to store access information, and each access information list isspecific to one user.

User 120 may send an access request for metadata (hereinafter, referredto as “target metadata”) to node 130 (such as node 130-1) in dataprotection system 110. In some embodiments, user 120 may log in to node130-1 and send an access request to node 130-1. User 120 may be anycomputing device, for example but not limited to, a distributedcomputing system, a mainframe, a server, a personal computer, a desktopcomputer, a laptop computer, a tablet computer, a wearable device, etc.

The access request may include an identification of the target metadata,for example, any appropriate information that can uniquely identify thetarget metadata, such as the name and hash value of the target metadata.Node 130-1 may determine whether access information (hereinafter,referred to as “target access information”), such as access information140-1, corresponding to the identification is stored on node 130-1 basedon the identification of the target metadata. For example, node 130-1may determine whether there is target access information correspondingto the identification in the stored access information list for user120.

If the target access information is stored on node 130-1 and the targetaccess information has not expired, node 130-1 may send metadata contentin the stored target access information to user 120 as the targetmetadata, which can significantly improve the speed at which user 120acquires the target metadata.

If the target access information is not stored on node 130-1, or thetarget access information has expired, node 130-1 will send theidentification of the target metadata to other nodes (such as nodes130-2 and 130-3) in data protection system 110, and receive the targetmetadata from the other nodes, thereby still ensuring that user 120 canacquire the target metadata.

In this way, the solution stores the access information in the localnode where the user logs in, so that the local node may quickly providethe user with the metadata content in the access information as thetarget metadata. In addition, since the access information is userspecific, it can support searching according to the user's searchpreferences. Therefore, the storage efficiency and user experience maybe significantly improved.

The operations performed by node 130-1 will be described below in detailwith reference to FIG. 2 to FIG. 6 . FIG. 2 shows a flowchart of method200 for storage management according to some embodiments of the presentdisclosure. For example, method 200 may be performed by node 130-1 asshown in FIG. 1 . It should be understood that method 200 may furtherinclude additional steps that are not shown and/or may omit the shownsteps, and the scope of the present disclosure is not limited in thisaspect. For ease of understanding, method 200 will be described withreference to FIG. 3 to FIG. 6 .

At 210, node 130-1 receives an access request for target metadata from auser. The access request includes an identification of the targetmetadata. At 220, node 130-1 acquires target access information (such asaccess information 140-1) corresponding to the identification from a setof access information for the user based on the identification of thetarget metadata. The target access information records informationrelated to an access to the target metadata.

FIG. 3 shows a schematic diagram of an example of access information 140according to some embodiments of the present disclosure. As shown inFIG. 3 , access information 140 may include metadata identification 310,metadata content 320, update time 330 of the access information, and/oracquisition count 340 of the access information.

For example, metadata identification 310 may be any appropriateinformation that can uniquely identify the metadata, such as the nameand hash value of the metadata. Metadata content 320 may be indexinformation for addressing the metadata, description information of themetadata, and the like. Update time 330 of the access information is thetime when the access information was updated last time. Acquisitioncount 340 of the access information is the number of times the accessinformation is acquired or searched for.

Update time 330 of the access information may be used to determinewhether the metadata content stored in node 130 has expired, so as todetermine whether to return the target metadata from the local node oracquire updated target metadata from other nodes.

In addition, in some embodiments, in order to save the storage space ofnode 130, the quantity of access information of node 130 for each usermay be limited. In this case, replacement algorithms such as leastrecently used (LRU) and first-in-first-out (FIFO) may be used to managethe access information stored in node 130 for each user. To this end,update time 330 of the access information and/or acquisition count 340of the access information may be used to implement replacement.

Referring back to FIG. 2 , at 230, if the target access information isacquired, node 130-1 determines the target metadata based on the targetaccess information. Specifically, the target access information isdivided into two situations: expired and unexpired. In some embodiments,access request may include initiation time of the access request. Inthis case, expiration of the target access information means that adifference between the initiation time of the access request and theupdate time in the target access information exceeds a predeterminedthreshold difference. When the target access information has it expired,then in one or more embodiments of the invention, this means that adifference between the initiation time and the update time is shorterthan the threshold difference.

To this end, node 130-1 determines the difference between the initiationtime and the update time, and performs different storage managementprocesses based on whether the difference exceeds the thresholddifference. It should be understood that in some embodiments, the accessrequest does not include initiation time. In this case, the differencemay also be determined based on the time when node 130-1 receives theaccess request. The storage management process in the case where thetarget access information has expired will be described in detail belowwith reference to FIG. 4 , and the storage management process in thecase where the target access information has not expired will bedescribed in detail with reference to FIG. 5 .

FIG. 4 shows a schematic diagram of an example of storage managementprocess 400 in the case where target access information has expiredaccording to some embodiments of the present disclosure. Since targetaccess information 140-1 in node 130-1 has expired, node 130-1 will notreturn the metadata content in expired target access information 140-1as the target metadata, but will search for unexpired target metadata inother nodes. To this end, at 420, node 130-1 may send the identificationof the target metadata to the other nodes among the plurality of nodes.At 430, node 130-1 may receive the target metadata from the other nodes.Then, at 440, node 130-1 may provide user 120 with the target metadata.

In some embodiments, node 130-1 may also update stored target accessinformation 140-1. Specifically, node 130-1 may update the metadatacontent in target access information 140-1 based on the unexpired targetmetadata received from the other nodes. In addition, node 130-1 mayupdate the update time in target access information 140-1 based on theinitiation time of the access request. Alternatively, node 130-1 mayalso update the update time in target access information 140-1 based onthe time when the target metadata is received. Further, since targetaccess information 140-1 is acquired, node 130-1 may increment theacquisition count in target access information 140-1.

FIG. 5 shows a schematic diagram of an example of storage managementprocess 500 in the case where target access information has not expiredaccording to some embodiments of the present disclosure. Since targetaccess information 140-1 in node 130-1 has not expired, node 130-1 maydetermine the metadata content in the target access information as thetarget metadata, and at 520, node 130-1 may provide user 120 with thetarget metadata.

In some embodiments, although target access information 140-1 in node130-1 has not expired, it may not be the latest target metadata. In thiscase, node 130-1 may also update stored target access information 140-1.Specifically, at 530, node 130-1 may send the identification of thetarget metadata to the other nodes among the plurality of nodes. At 540,node 130-1 may receive updated target metadata from the other nodes.Node 130-1 may update the metadata content in target access information140-1 based on the updated target metadata. In addition, node 130-1 mayupdate the update time in target access information 140-1 based on theinitiation time of the access request. Alternatively, node 130-1 mayalso update the update time in target access information 140-1 based onthe time when the updated target metadata is received. Further, sincetarget access information 140-1 is acquired, node 130-1 may incrementthe acquisition count in target access information 140-1.

The above describes the case where the target access information existsin node 130-1. However, in some cases, the target access informationdoes not exist in node 130-1. In this case, the target accessinformation cannot be acquired from the set of access information foruser 120. FIG. 6 shows a schematic diagram of an example of storagemanagement process 600 in the case where target access information isnot acquired according to some embodiments of the present disclosure.

As shown in FIG. 6 , if the target access information is not acquiredfrom the set of access information for user 120, at 620, node 130-1 maysend the identification of the target metadata to the other nodes amongthe plurality of nodes. At 630, node 130-1 may receive the targetmetadata from the other nodes. Then, at 640, node 130-1 may provide user120 with the target metadata.

In some embodiments, node 130-1 may create the target accessinformation, and store the target access information, for example, thetarget access information is added to an access information listspecific to user 120. In some embodiments, node 130-1 may create thetarget access information based on the identification of the targetmetadata, the target metadata received from the other nodes, theinitiation time of the access request, and a predetermined initial valueof the acquisition count.

In some embodiments, the quantity of user 120-specific accessinformation that node 130-1 can store may be limited. In this case,replacement algorithms such as least recently used (LRU) andfirst-in-first-out (FIFO) may be used to manage a set of user120-specific access information stored in node 130. For example, node130-1 may determine to-be-replaced access information from the set ofaccess information. The to-be-replaced access information may satisfythe following conditions: the update time of the to-be-replaced accessinformation exceeds a predetermined threshold time, and/or theacquisition count of the to-be-replaced access information exceeds apredetermined threshold count. For example, node 130-1 may replace theaccess information with the earliest update time, or replace the accessinformation with the least acquisition count. Alternatively, node 130-1may also perform replacement by considering both the update time and theacquisition count. After determining the to-be-replaced accessinformation, node 130-1 may replace the to-be-replaced accessinformation with the target access information.

Further, in some embodiments, when user 120 logs in to node 130-1, theset of access information specific to user 120 may not exist on node130-1. To this end, when user 120 logs in to data protection system 110via node 130-1, node 130-1 may determine whether the set of accessinformation for user 120 is stored in node 130-1. If the accessinformation has not been stored in node 130-1, node 130-1 may acquirethe access information from the other nodes among the plurality ofnodes. In this way, even if the user logs in to data protection system110 at different times and in different geographic locations, it canalso ensure the consistent user experience during the backup searchingprocess.

In addition, when user 120 logs out of data protection system 110 vianode 130-1, node 130-1 may also notify the other nodes among theplurality of nodes of the updated access information in the set ofaccess information for user 120. In this way, other nodes may know toacquire the updated access information from node 130-1.

FIG. 7 shows a schematic block diagram of example device 700 that can beconfigured to implement an embodiment of the present disclosure. Forexample, data protection system 110 as shown in FIG. 1 may beimplemented by device 700. As shown in the figure, device 700 includescentral processing unit (CPU) 710 that may perform various appropriateactions and processing according to computer program instructions storedin read-only memory (ROM) 720 or computer program instructions loadedfrom storage unit 780 to random access memory (RAM) 730. Variousprograms and data required for operations of device 700 may also bestored in RAM 730. CPU 710, ROM 720, and RAM 730 are connected to eachother through bus 740. Input/output (I/O) interface 750 is alsoconnected to bus 740.

A plurality of components in device 700 are coupled to I/O interface750, including: input unit 760, such as a keyboard and a mouse; outputunit 770, such as various types of displays and speakers; storage unit780, such as a magnetic disk and an optical disc; and communication unit790, such as a network card, a modem, and a wireless communicationtransceiver. Communication unit 790 allows device 700 to exchangeinformation/data with other devices over a computer network such as theInternet and/or various telecommunication networks.

The various processes and processing described above, for example,methods 200 and 400-600, may be performed by processing unit 710. Forexample, in some embodiments, methods 200 and 400-600 may be implementedas a computer software program that is tangibly included in amachine-readable medium such as storage unit 780. In some embodiments,part or all of the computer program may be loaded and/or installed ontodevice 700 via ROM 720 and/or communication unit 790. When the computerprogram is loaded into RAM 730 and executed by CPU 710, one or moreactions of methods 200 and 400-600 described above may be implemented.

The present disclosure may be a method, an apparatus, a system, and/or acomputer program product. The computer program product may include acomputer-readable storage medium on which computer-readable programinstructions for performing various aspects of the present disclosureare loaded.

The computer-readable storage medium may be a tangible device capable ofretaining and storing instructions used by an instruction-executingdevice. For example, the computer-readable storage medium may be, but isnot limited to, an electrical storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any appropriate combination of theabove. More specific examples (a non-exhaustive list) of thecomputer-readable storage medium include: a portable computer disk, ahard disk, a random access memory (RAM), a read-only memory (ROM), anerasable programmable read-only memory (EPROM or flash memory), a staticrandom access memory (SRAM), a portable compact disk read-only memory(CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk,a mechanical coding device such as a punch card or protrusions in agroove on which instructions are stored, and any appropriate combinationof the above. The computer-readable storage medium used here is notconstrued as transient signals themselves, such as radio waves or otherfreely propagating electromagnetic waves, electromagnetic wavespropagating through waveguides or other transmission media (for example,optical pulses through fiber-optic cables), or electrical signalstransmitted through electrical wires.

The computer-readable program instructions described herein can bedownloaded from a computer-readable storage medium to variouscomputing/processing devices, or downloaded to an external computer orexternal storage device via a network such as the Internet, a local areanetwork, a wide area network, and/or a wireless network. The network mayinclude copper transmission cables, optical fiber transmission, wirelesstransmission, routers, firewalls, switches, gateway computers, and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives a computer-readable programinstruction from the network and forwards the computer-readable programinstruction for storage in the computer-readable storage medium in eachcomputing/processing device.

The computer program instructions for performing the operations of thepresent disclosure may be assembly instructions, Instruction SetArchitecture (ISA) instructions, machine instructions, machine-relatedinstructions, microcode, firmware instructions, status setting data, orsource code or object code written in any combination of one or moreprogramming languages, including object-oriented programming languages,such as Java, Smalltalk, and C++, as well as conventional proceduralprogramming languages, such as “C” language or similar programminglanguages. The computer-readable program instructions may be executedentirely on a user computer, executed partly on a user computer,executed as a stand-alone software package, executed partly on a usercomputer while executed partly on a remote computer, or executedentirely on a remote computer or a server. In a case where a remotecomputer is involved, the remote computer can be connected to a usercomputer through any kind of networks, including a local area network(LAN) or a wide area network (WAN), or can be connected to an externalcomputer (e.g., connected through the Internet using an Internet serviceprovider). In some embodiments, an electronic circuit, such as aprogrammable logic circuit, a field programmable gate array (FPGA), or aprogrammable logic array (PLA), can be customized by utilizing statusinformation of the computer-readable program instructions. Theelectronic circuit may execute the computer-readable programinstructions to implement various aspects of the present disclosure.

Various aspects of the present disclosure are described here withreference to flowcharts and/or block diagrams of the methods, theapparatuses (systems), and the computer program products according tothe embodiments of the present disclosure. It should be understood thateach block in the flowcharts and/or block diagrams and a combination ofblocks in the flowcharts and/or block diagrams may be implemented bycomputer-readable program instructions.

The computer-readable program instructions may be provided to aprocessing unit of a general purpose computer, a special purposecomputer, or another programmable data processing apparatus to produce amachine, such that the instructions, when executed by the processingunit of the computer or another programmable data processing apparatus,generate an apparatus for implementing the functions/actions specifiedin one or more blocks in the flowcharts and/or block diagrams. Thecomputer-readable program instructions may also be stored in acomputer-readable storage medium, to cause a computer, a programmabledata processing apparatus, and/or other devices to work in a specificmanner, such that the computer-readable medium storing the instructionsincludes an article of manufacture that contains instructions forimplementing various aspects of the functions/actions specified in oneor more blocks in the flowcharts and/or block diagrams.

The computer-readable program instructions may also be loaded onto acomputer, other programmable data processing apparatuses, or otherdevices, so that a series of operating steps are performed on thecomputer, other programmable data processing apparatuses, or otherdevices to produce a computer-implemented process, so that theinstructions executed on the computer, other programmable dataprocessing apparatuses, or other devices implement the functions/actionsspecified in one or more blocks in the flowcharts and/or block diagrams.

The flowcharts and block diagrams in the accompanying drawings show thearchitectures, functionalities, and operations of possibleimplementations of the system, the method, and the computer programproduct according to a plurality of embodiments of the presentdisclosure. In this regard, each block in the flowcharts or blockdiagrams may represent a module, a program segment, or part of aninstruction, the module, program segment, or part of an instructionincluding one or more executable instructions for implementing specifiedlogical functions. In some alternative implementations, the functionsmarked in the blocks may also occur in an order different from thatmarked in the accompanying drawings. For example, two successive blocksmay actually be performed basically in parallel, or they may beperformed in an opposite order sometimes, depending on the functionsinvolved. It should be further noted that each block in the blockdiagrams and/or flowcharts as well as a combination of blocks in theblock diagrams and/or flowcharts may be implemented by using a dedicatedhardware-based system for executing specified functions or actions or bya combination of dedicated hardware and computer instructions.

The embodiments of the present disclosure have been described above. Theabove description is illustrative, rather than exhaustive, and is notlimited to the disclosed embodiments. Numerous modifications and changesare apparent to those of ordinary skill in the art without departingfrom the scope and spirit of the various illustrated embodiments. Theselection of terms as used herein is intended to best explain theprinciples and practical applications of the various embodiments ortechnical improvements to technologies on the market, or to enable otherpersons of ordinary skill in the art to understand the embodimentsdisclosed herein.

The invention claimed is:
 1. A method for storage management,comprising: receiving an access request for target metadata from a userat a node among a plurality of nodes included in a data protectionsystem, wherein the access request comprises an identification of thetarget metadata and initiation time of the access request; based on theidentification, acquiring target access information corresponding to theidentification from a set of access information for the user, whereinthe target access information records information related to access tothe target metadata, wherein a replacement model is used to manage theset of access information stored in the node; when the target accessinformation is acquired, determining the target metadata based on thetarget access information; and acquiring the target metadata, whereinacquiring the target metadata comprises: determining a differencebetween the initiation time and update time of the target accessinformation; when the difference exceeds a threshold difference, sendingthe identification to other nodes of the plurality of nodes; receivingthe target metadata from the other nodes; and providing the targetmetadata to the user; when the difference is lower than the thresholddifference, determining a metadata content in the target accessinformation as the target metadata; sending the identification to theother nodes; receiving updated target metadata from the other nodes;based on the updated target metadata, updating the metadata content;based on the initiation time, updating the update time in the targetaccess information; and providing the updated target metadata to theuser.
 2. The method according to claim 1, wherein the target accessinformation comprises at least one selected from a group consisting of:a metadata identification; the metadata content; the update time; and anacquisition count.
 3. The method according to claim 2, furthercomprising: in response to the target access information being acquired,incrementing the acquisition count in the target access information. 4.The method according to claim 1, further comprising: when user logs intothe data protection system via the node, determining whether the set ofaccess information is stored in the node; and when the set of accessinformation has not been stored in the node, acquiring the set of accessinformation from other nodes in the plurality of nodes.
 5. The methodaccording to claim 1, further comprising: when user logs out of the dataprotection system via the node, notifying other nodes of the pluralityof nodes of an updated access information in the set of accessinformation.
 6. An electronic device, comprising: at least oneprocessing unit; and at least one memory coupled to the at least oneprocessing unit and storing instructions configured to be executed bythe at least one processing unit, wherein the instructions, whenexecuted by the at least one processing unit, cause the electronicdevice to perform actions comprising: receiving an access request fortarget metadata from a user at a node among a plurality of nodesincluded in a data protection system, wherein the access requestcomprises an identification of the target metadata and initiation timeof the access request; based on the identification, acquiring targetaccess information corresponding to the identification from a set ofaccess information for the user, wherein the target access informationrecords information related to access to the target metadata, wherein areplacement model is used to manage the set of access information storedin the node; when the target access information is acquired, determiningthe target metadata based on the target access information; andacquiring the target metadata, wherein acquiring the target metadatacomprises: determining a difference between the initiation time andupdate time of the target access information; when the differenceexceeds a threshold difference, sending the identification to othernodes of the plurality of nodes; receiving the target metadata from theother nodes; and providing the target metadata to the user; when thedifference is lower than the threshold difference, determining ametadata content in the target access information as the targetmetadata; sending the identification to the other nodes; receivingupdated target metadata from the other nodes; based on the updatedtarget metadata, updating the metadata content; based on the initiationtime, updating the update time in the target access information; andproviding the updated target metadata to the user.
 7. The electronicdevice according to claim 6, wherein the target access informationcomprises at least one selected from a group consisting of: a metadataidentification; the metadata content; the update time of the targetaccess information; and an acquisition count of the target accessinformation.
 8. A computer program product tangibly stored on anon-transitory computer-readable medium and comprisingmachine-executable instructions, wherein the machine-executableinstructions, when executed, cause a machine to perform steps of amethod, the method comprising: receiving an access request for targetmetadata from a user at a node among a plurality of nodes included in adata protection system, wherein the access request comprises anidentification of the target metadata and initiation time of the accessrequest; based on the identification, acquiring target accessinformation corresponding to the identification from a set of accessinformation for the user, wherein the target access information recordsinformation related to access to the target metadata, wherein areplacement model is used to manage the set of access information storedin the node; when the target access information is acquired, determiningthe target metadata based on the target access information; andacquiring the target metadata, wherein acquiring the target metadatacomprises: determining a difference between the initiation time andupdate time of the target access information; when the differenceexceeds a threshold difference, sending the identification to othernodes of the plurality of nodes; receiving the target metadata from theother nodes; and providing the target metadata to the user; when thedifference is lower than the threshold difference, determining ametadata content in the target access information as the targetmetadata; sending the identification to the other nodes; receivingupdated target metadata from the other nodes; based on the updatedtarget metadata, updating the metadata content; based on the initiationtime, updating the update time in the target access information; andproviding the updated target metadata to the user.